Radioactivity in Bottled Drinking Water from Greater Dhaka City and Concomitant Ingestion Doses to Consumers

Activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K radionuclides were determined in various brands of bottled drinking water commonly available in the local markets of Greater Dhaka City; additionally, the annual effective dose following the ingestion pathway was assessed. Radioactivity of ²²⁶Ra in the bottled water (purified, mineral, and drinking) samples varied from 0.61 ± 0.27 Bq L^-1 to 10.64 ± 1.34 Bq L^-1 with a mean value of 4.73 ± 1.02 Bq L^-1. For ²³²Th, the concentration ranged between 0.35 ± 0.27 Bq L^-1 and 5.71 ± 3.37 Bq L^-1 with a mean of 2.97 ± 1.61 Bq L^-1; for ⁴⁰K, it ranged from 3.48 ± 2.92 Bq L^-1 to 93.58 ± 26.74 Bq L^-1 with a mean of 36.31 ± 10.63 Bq L^-1. Purified bottled water exhibited the highest activity concentrations of ²²⁶Ra and ⁴⁰K, whereas drinking water showed the highest ²³²Th concentration compared to purified and mineral bottled water samples. Infants received higher annual ingestion doses compared to children and adults. The average value of the threshold consumption rate remained below the limit. The ²²⁶Ra shows statistical significance, whereas ²³²Th and ⁴⁰K are the opposite; ²²⁶Ra shows greater heterogeneity.